NEW EXTERNAL LOOP 'AIR-LIFT' BIOREACTOR FOR TREATING LIQUID EFFLUENT

摘要

An innovative method for biological treatment has proven to be very effective and less expensive for treating various soluble and colloidal pollutants in agricultural, industrial and urban liquid waste. The present invention relates to an industrial device that allows degradation of the organic pollutant load of effluent by biological processing. The technique has been successfully tested in the case of liquid waste with a high biological load. The treatment was carried out in the presence of microalgae. The depollution of the waste in the external loop air-lift bioreactor that has been developed occurs with a continuous supply of the waste that is to be treated and through the contribution of oxygenation, for the first time using ventilation in this type of apparatus. The invention is focused on administering a significant amount of ambient air containing the oxygen and carbon dioxide that is required for biological treatment in the presence of microalgae. This contribution is provided, for the first time in this type of reactor, through ventilation that allows a pressure differential to be created between the outside and the inside of the reactor, which allows a considerable air flow to be routed towards the inside of the apparatus. Compared to the other treatment techniques that are applied in similar reactors, the present method has proven to be highly advantageous in terms of the effectiveness of the treatment and of energy consumption. For treating agricultural waste tested in a 35 litre capacity apparatus, COD reduction effectiveness of the order of 87.35% and a bleaching ratio of the order of 90.46% were recorded for energy consumption of 0.8 W/kg of COD eliminated over 12 hours of treatment.